Window assembly



Aug. 8, 1939. w, BAYLEY 2,168,922

WINDOW ASSEMBLY Original Filed June 1, 1936 3 Sheets-Sheet l III VEN TORFIG. 2 BY WILLIAM U. BKYLEY SA 7 RNEY Aug. 8, 1939. w. D. BAYLEY WINDOWASSEMBLY Original Filed Juhe 1-, 1936 3 Sheets-Sheet 2 FIG. I5

I INVENTOR WILLIAM 115A LEY FIGG 8, 1939. w. D. BAYLEY 2,168,922

WINDOW ASSEMBLY Original Filed June 1, 1936 3 Sheets-Sheet 3 FIGB H6 H6FIG '5 FIG/4 FIG/l FIG/O INVENTOR- BY WILLIAM B. BAYLEY HISA ORNPatented Aug. 8, 1939 UNITED STATES PATENT OFFICE Application June 1,1936, Serial No. 82,846 Renewed December 27, 1938 22 Claims.

This invention relates to window assemblies and in more particular to awindow assembly adapted to receive the glazing either from the outsideor from the inside.

In windowassemblies for some types of structures it is preferable tohave the glass pane inserted from the inside, so as to have the glassfit snugly in one direction. This is especially the case in commercialwindows, such as factories, ofiice buildings and the like, where it isnot convenient to insert the glass pane of the window from the outside,and where there is no objection to a rough putty job on two of the bars.

In other installations putty is objectionable on the inside. This isespecially the case in residences, apartment houses and exclusive oflicebuildings. In addition to the foregoing, in some types of penalinstitutions it is desirable to have the putty out of reach of theinmates.

In order to promptly supply-the various demands for window structures,the manufacturer is required to keep on hand a great variety of types,including windows adapted to be glazed and puttied from the inside, andother windows adapted to be glazed and puttied from the outside. Theformer type of window is well adapted to installations where theaesthetic appeal is not important.

Whenever T-bars are used in window structures, all the flanges or headsof the T-bars are usually placed on the same side of the glazing,permitting the webs or stems of the T to project between the edges ofthe window panes, so as to lie in part on the other side of the glazing.By disposing the flanges of one set of bars on the outside and of theother set of bars on the inside, it is possible to get portions of thebars a greater effective distance from the neutral plane of the entireassembly, thereby increasing the strength. In addition thereto, putty isbetter supported on both sides and consequently it is possible to shipthe windows glazed. As is well known to those skilled in the science ofthe strength of materials, such window structures offer a far greaterresistance to wind pressures from one side than from the other.

An object of this invention is to provide a universal window that may beglazed either from the outside or from the inside.

Another object of this invention is to provide a window that isconstructed to be equally strong to wind resistance from either side.

Another object of this invention is to provide a window structure thatis cheap, easily manufactured, durable, dependable, eflicient, of amplestrength and water-tight.

Another object of this invention is to provide a dual closure.

Another object of this invention is to provide a window that may bereadily screened.

Another object of this invention is to provide clearance for an operatormedially positioned with respect to the closure.

7 Another object of this invention is to provide interlocking joints forthe transversely disposed intersecting muntin bars.

Other objects and advantages reside in the construction of parts, thecombination thereof and the mode of operation, as will becomemoreapparent from the following description.

Fig. 1 discloses a perspective outside view of my preferredmodification.

Fig. 2 is a sectional view taken substantially on line 2-2 of Fig. 1.

Fig. 3 is a sectional view taken substantially on line 3-3 of Figs. 1and 2.

Fig. 4 is a vertical sectional view similar to Fig. 3, showing anothermodification, taken substantially on line 4-4 of Fig. 1 with closures inclosed position and on line 4-4 of Fig. 5.

Fig. 5 is a sectional view taken substantially on line 5-5 of Figs. 1and 4.

Fig. 6 is a fragmentary perspective view of a weather stripping unit.

Fig. '1 is a fragmentary sectional view taken substantially on line 1--1of Fig. 1.

Fig. 8 shows a horizontal bar with the cutout therein for receiving thevertical bar.

Fig. 9 is a fragmentary side elevation of the vertical bar beforeassembly with the horizontal bar disclosed in Fig. 8 into the structureshown in Fig. 7.

Fig. 10 is a fragmentary sectional view taken similar to Fig. 7 showinganother modification.

Fig. 11 is a fragmentary view of the horizontal bar having the webthereof cut and portions deflected, preparatory to the reception of thevertical bar.

Fig. 12 is a vertical bar cut in readiness for assembly with the barshown in Fig. 11, resulting in the structure shown in Fig. 10.

Figs. 13 and 14 disclose vertical and horizontal fragmentary sectionalviews of another adaptation wherein glazing has been mounted in theventilating area to augment that of the movable closure.

Fig. 15 shows a sectional view of another modification.

Referring to the drawings, the reference characters l and I2 indicatethe top and sill members of the window frame and the reference characterll the outside vertical frame members of the window. A plurality ofvertical T-shaped muntin bars it have their upper ends fixed in the topframe member In and the lower ends in the sill member I2. The flanges 2.of the muntin bars [6 are preferably located on the outside of theglazing. A plurality of horizontal muntin bars l8 intersect andinterlock the vertical muntin bars It so as to divide the window into aplurality of spaces 20, some of which are glazed, leaving others vacantfor ventilating area. The flanges 30 of the muntin bars II are locatedon the inside of the glazing. This arrangement permits the use of glasspanes inserted from the outside, so as to present a neat appearance tothe window from the exterior, the putty being applied from the outside.In other windows, the glass panes may be inserted from the inside. Insuch installations the window may be puttied from the inside of thebuilding, thereby facilitating the glazing of the fixed spaces. Thewindow permits the glazer to stand on the inside of the building andreach the outside through the ventilating area to putty the fixedglazing.

This window assembly is so constructed that differential air pressuresbetween the outside and the inside of the building are absorbed by oneset of bars when the pressure is higher on the inside than on theoutside and by the other set of bars when the pressure is higher on theoutside than on the inside. This arrangement resuits in a universalwindow that may be carried in stock whether the glazing is to beinserted from the inside or the outside. It also results in a windowwherein the resistance to diflerential pressures or applied forces isapproximately the same whether the force is applied from the outside ofthe window or from the inside of the window.

The intersection of the bars i6 and I8 is preferably so constructed thatthe bars may be readily assembled with the minimum amount of labor andtime, the finished assembly resulting in a satisfactory finishedproduct.

Referring to Fig. 8, the muntin bar II is provided with a cutoutT-shaped portion designated by the reference character I! that is ofsuch a proportion as to properly receive the muntin bar l6. After thebars are assembled, the ends of the flanges 30 are suitably welded sothat the opening l9 does not materially weaken the bar ll. In thismodification the vertical bar l6 has not been severed in any manner andtherefore it has its original strength. In the modification disclosed inFigs. 10, 11 and 12 the horizontal muntin bar I it has the web severedat 9, the outer lips III of the web being deflected outwardly so as toreceive the complementary bar H8 having the web cut away, as shown atI23, to receive the flange I28 of the bar I I6. After the bar H8 hasbeen inserted into the seat provided therefor in bar H, the lips I II'are straightened so as to present an uninterrupted surface along theinside of the window. The ends of the lips i2i are preferably weldedtogether.

The ventilating spaces 22 which have been shown along the center of thewindow assembly disclosed in Fig. 2, are provided with a pair ofoutwardly swinging closures 32. These closures are formed from verticalmuntin bars 36, supported in a frame including the angle bars 31. Themuntin bars 38 and the angle bars 31 are provided with flanges on theoutside of the glazing. The closure 32 also includes horizontal muntinbars 38, having the flanges on the inside of the glazing, so as toharmonize with the remainder of the window structure. Whenever thewindow assembly is used as a detention window, the vertical andhorizontal muntin bars i6 and I8 extend continuously across theventilating area. The muntin bars functioning as detention bars acrossthe ventilating area may be offset so as to permit the closures 32 to becoplanar with the main body portion of the window. or the detention barsacross the ventilating area may be aligned with the muntin bars acrossthe fixed spaces, in which event the closures 32 are oil'set from theplane of the main window portion, as clearly shown in Fig. 3.

Individual screens 40 may be used to prevent the escape of bodiesthrough the ventilating areas 22. Due to the outside flanges 28 and theinside flanges 30, the individual screens 40 may be seated in thepockets formed by these flanges. For some types of installations thescreen units 40 may be loosely inserted and in others they may beattached in any suitable manner.

Whenever the ventilating area of a window is screened and the'screen islocated between the closure and the inside of the window, the operatorpresents a problem. In some installations the operators have beenmounted in the sill of the window; but this is objectionable in that theoperator engages an extreme end of the closure. In the modificationdisclosed herein a U-shaped channel 42 extending across the ventilatingarea has been substituted for one of the T-bars i8. This U-shapedchannel 42 has a flange 44 that provides a suitable seat for the screenframe 40 located adjacent thereto. The closures 32 have been providedwith channels 48, substantially U-shaped; but disposed in oppositedirections and directly opposite the U-shaped channel 42. The channels4' have been provided with glass abutting flanges ll. The channels 42and 46 cooperate to provide a suitable passage and encasement for theoperator of the casement windows, which operator has not been shown, asthis will form the subject matter of a separate application for LettersPatent.

In metallic windows a close and tight fit between the frame bounding theventilating area and the closure frame presents a problem.Various'attempts have been made to solve this problem, some of which arerather expensive and therefore prohibitive for general use. In themodification disclosed herein a resilient weather stripping member 50,which has a substantially T-shaped cross sectional area, is mountedintermediate the outer flanges of the outside top and bottom muntin barsof the closure 32 and the frame of the window. Members 50 are preferablymade from some resilient material, such as live rubber, which isflexible. The outside flanges 52 are adapted to abut the outside flangesof the closure and the head of the T abutts the fixed flanges boundingthe ventilating area. A plurality of stems 54 equally spaced along thebody of member Eli, are provided with enlarged heads 56, as best seen inFig. 6, adapted to be projected or inserted in suitable holes in theflanges of the closure, the enlarged heads preventing the removal. orthe dropping out of the insulating strip II. Whenever the life of therubber deteriorates, new insulating strips I may be substituted for theworn members. Instead of the insulating strips I being carried by theclosure, such strips may be attached to the fixed frame bounding theventilating area equally as well.

The vertical angle bars 31 support housing members 58 enclosing theweather stripping members 59 adapted to form a water and air-tight unionbetween the angle bars 31 and the vertical muntin bars l6 bounding theventilating area. As the flanges of the center muntin bar extendingalong the common inside edge of the closures 32 may not be suilicientlywide to accommodate the felt or pliable weather stripping members 59, asuitable sheet metal cap 6| may be fixedly at.- tached to the flanges ofthis vertical muntin bar. Member GI provides a suitable seat for thefelt weather stripping members 59. It is to be noted that the contour ofthe outside of the muntin bars bounding the ventilating area isirregular in that the webs of the horizontal muntin bars project beyondthe flanges of the vertical muntin bars.

For some installations it may be desirable to have a ventilating areaextend partially across or entirely across the bottom of the window andclosed by a closure angularly disposed when in 'open position, so as toproject the air upwardly into the room. In Fig. 1 such a closure ofmetal has been shown by reference character 60. This closure is pivotedat 62 to the sill of the window and is provided with an angular member64 adapted to abut against the web 65 of the sill member I2. Thisangular member 64 houses a felt or other suitable weather strippingmember 66. The sides, the top and the bottom of the closure for theventilating area of the window may be provided with insulating members50, much the same as those disclosed and described in connection withthe closure 32.

As may best be seen by referring to Figs. 1, 4 and 5, ventilating areas10, disposed at the top of the window one on each side of the closures32, are closed by sheet metal closures 12. The upper portion of member12 is provided with a bead I4 encircled by a bead 16 of member I8fixedly attached to the frame member III. The sides and bottom of thesheet metal closure I2 may be provided with outwardly projecting flanges19, the one extending alongthe bottom sloping so as to provide awatershed. The top and sides of the closure 12 may be provided withresilient weather stripping members 50 adapted to engage the flanges ofmembers I0, I4 and I6. These weather stripping members 50 may be fixedlyattached to the flanges of the fixed portion of the window.

An inwardly projecting edge 80 may resiliently engage the outer edge ofthe web of the muntin bar I8. This edge or lip 80 may be integral withthe sheet metal closure I2 or it may constitute a suitable resilientmember inserted into the bight of the fold constituting the flange I9,as best seen in Fig. 4. Member 80 may be of sheet metal, fibrousmaterial or rubber, depending upon the requirements and the materialsavailable.

The screen frames 40 or the window panes as the case may be, areinserted by advancing one edge over the near flange and toward the webuntil the opposite edge clears the opposite flange. The screen frame orthe window pane is dimensioned to permit such insertion.

In some climates and certain types of installations it may be desirableto provide double glazing for the window. That being the case, it may attimes be desirable to substitute for the screens 40, window sectionsI30, which include a pane of glass I32 provided with a resilient frameI34 made of rubber or other suitable flexible material.

The rubber frame I34 may be provided with a lip I36 adapted to engagethe sides of the stem or webs of the T-bars I6 or I8 bounding the vacantspaces of the ventilating area. These window sections are preferablyremovably mounted, so that as the weather moderates and it is desirableto have more ventilation, the window sections I30 may be removed and thescreen sections 40 substituted therefor.

In the modification disclosed in Fig. 15 a glass retaining member I40provided with oppositely disposed flanges I42 is inserted over the edgeof the web of the muntin bar I 6 and held in position by suitable screwsor retaining members I44. This glass retaining member I40 is preferablyused on the interior of the window where it is desirable to have theminimum amount of putty exposed on the interior of the building.Although it has been shown and used with the vertical muntin bar, itmight also be used in connection with similar horizontal muntin bars.

Although the preferred modifications of the device have been described,it will be understood that within the purview of this invention variouschanges may be made in the form, details, proportion and arrangement ofparts which generally stated consist in a device capable of carrying outthe objects set forth, in the novel .parts, combination of parts andmode of operation, as. disclosed and defined in the appended claims;

Having thus described my invention, I claim:

1. In a window assembly which may be glazed from either side, thecombination of a set of muntin bars having flanges on the inside of theglazing presenting a flat surface on the interior of the window, saidmuntin bars having outwardly. projecting webs terminating in spacedrelation with the outside surface of the glazing, with a second set ofmuntin bars intersecting the first set ofbars, said second set of muntinbars having flanges mounted on the outside of the glazing, said flangespresenting substantially a flat surface on the outside of the window,the muntin bars of the second set having inwardly projecting websterminating in spaced relation with respect to the inner surface of thewindow whereby the window panes may be inserted from either side.

2. In a window assembly a set of muntin bars having all flanges disposedon the; inside of the glazing, said flanges presenting a smooth innersurface, each of said muntin bars having a web extending outwardly andterminating in spaced relation with respect to the outer surface of thewindow, and a second set of muntin bars having all flanges disposed onthe outside of the window, said flanges presenting an outer smoothsurface, the muntin bars of said second set having inwardly projectingwebs disposed in spaced relation with respect to the inner surface ofthe glazing whereby the window panes may be inserted from either side.

3. In a window assembly wherein the window panes may be inserted fromeither side, the combination including a set of horizontal muntin barshaving flanges on the inside of the glazing presenting a smooth innersurface and having webs projecting in spaced relation from the outersurface of the glazing, and a set of vertical muntin bars having flangesdisposed on the outside of the glazing, said flanges presenting a smoothouter surface, said second set of bars having webs terminating in spacedrelation from the inner surface of the window, the bars of the secondset interlocking the bars of the first set, the webs of each set of barsextending beyond the flanges of the other set so as to extend fartheraway from the neutral plane than the distance from the neutral plane tothe extremity of the flanges.

4. In a window assembly a set of horizontal muntin bars having theflanges disposed on one side of the glazing and webs projecting betweenthe edges of the glazing on the other side thereof, a second set oftransversely disposed muntin bars interlocking said first set of barsbut having the flanges on the opposite side of the glazing from theflanges of the first set and webs projecting intermediate the glazing,the webs of one set projecting beyond the flanges of the other set, saidmuntin bars dividing the window into a plurality of spaces some of whichare glazed leaving a space vacant for ventilating area, said ventilatingarea being bounded by muntin bars the webs projecting beyond the flangespresenting an irregular surface around the ventilating area, a closurefor the ventilating area, and means disposed intermediate the closureand the muntin bars bounding the ventilating area for compensating forthe variations in the irregularities of the muntin bars bounding theventilating area.

5. In a window assembly a plurality of transversely disposed muntin barsdividing the window into a plurality of spaces some of which are glazedleaving a space vacant for ventilating area. the surface on at least oneside of the muntin bars being irregular so that the muntin bars boundingthe ventilating area present an irregular surface, a movable closure forthe ventilating area, and means disposed intermediate the closure andthe muntin bars bounding the ventilating area for compensating for theirregularities in the contour of the muntin bars.

6. In a window assembly for use with a window having a ventilating area,the combination including a frame bounding the ventilating area, amovable closure mounted in the ventilating area, said movable closureincluding a frame having an inwardly projecting flange, one side ofwhich has a plurality of aligned openings, and a weather strippingmember disposed intermediate the two frames for sealing the ventilatingarea when the closure therefor is in closed position, said weatherstripping member having a plurality of elongated projections extendingthrough said openings and terminating in enlarged portions for holdingthe member in position.

7. In a window assembly having a ventilating area, the combinationincluding a frame member bounding the ventilating area, a metallicclosure member movably mounted in the ventilating area, one of saidmembers having a plurality of aligned holes therein and a flangeextending parallel to the holes abutting the other member when theclosure is in closed position, and a weather stripping member disposedintermediate said members and extending along the flange for sealing theventilating area when the closure member is in closed position, saidweather stripping member having a plurality of elongated projectionsextending through said openings for supporting said weather strippingmember in fixed relation with respect thereto, said weather strippingmember being removably supported in said openings.

8. In a window assembly having a ventilating area, a frame memberbounding the ventilating area, a sheet metal closure movably mountedupon the frame member for closing the ventilating area, said framemember having an inwardly projecting flange abutting the frame, and

resilient means disposed intermediate the frame member and the sheetmetal closure, said resilient means being supported upon and attached tothe sheet metal closure.

9. In a window assembly adapted to be glazed from either side, thecombination including a plurality of vertical parallel muntin barshaving flanges on one side of the glazing and a plurality of horizontalmuntin bars having flanges on the other side of the glazing, said muntinbars dividing the window into a plurality of spaces some of which areglazed leaving a group of spaces vacant for a ventilation area, aclosure for said ventilation area, said closure including a plurality ofvertical muntin bars having the flanges on one side of the glazing and aplurality of horizontal muntin bars having the flanges on the oppositeside of the glazing.

10. In a window assembly the combination of a plurality of parallelmuntin bars having outwardly disposed glazing rabbets with a pluralityof parallel muntin bars transversely disposed with respect to said firstplurality, said second plurality having inwardly disposed glazingrabbets whereby the window may be glazed from either side.

11. In a window assembly adapted to be glazed from either side, thecombination of a set of vertical muntin bars having flanges disposed onone side of the glazing and webs extending between the edges of theglass panes, with a set of horizontal muntin bars having flangesdisposed on the opposite side of the glazing, said second set of muntinbars having webs extending between the edges of the glass panes anddirected in the opposite direction of the webs of the first set ofmuntin bars.

12. In a window assembly a plurality of horizontal parallel T-shapedmuntin bars having the flanges thereof disposed on one side of theglazing, means for supporting the vertical edges of the glazing, saidmeans including stems projecting between the glazing and merging intoshoulders integral therewith, said'shoulders overlying the side of thevertical edge of the glazing opposite the flanges of the T-shaped barsso as to support opposite sides of the glazing against the flanges ofthe T-shaped bars and the remaining sides of the glazing by saidshoulders oppositely disposed with respect to the flanges.

13. In a window assembly a frame surrounding a ventilating area, saidframe having inwardly projecting flanges along three sides thereof, aclosure unit for the ventilating area pivotally mounted along the fourthside of the frame, said closure unit supporting a resilient memberdisposed along three sides thereof and adapted to contact the inwardlyprojecting flanges of the frame when the closure is in closed position,means for limiting the movement of the closure to prevent excessivecompression of said resilient member, anda resilient member disposedalong the fourth side of the closure, said resilient member beingadapted to be compressed intermediate the frame surrounding theventilating area and the edge of the closure unit.

14. In a window assembly wherein the glass panes may be inserted fromeither side, the combination of a set of T-shaped muntin bars arrangedin parallel relation with a set of transversely disposed T-shaped muntinbars, the flanges of the first set being disposed on the in- .s'idef'of'the glazing and the flanges of the second differential pressuresfrom either side.

15. In a window assembly wherein the glass panes may be inserted fromeither side, the combination of a set of T-shaped muntin bars having theflanges thereof disposed on the inside of the glazing with acomplementary set of T-shaped muntin bars transversely arranged withrespect to the first muntin bars, said complementary set having theflanges disposed. on the outside of the glazing with the webs thereofprojecting inwardly, the webs of each set of bars being notched toreceive the flanges of the opposite set, the notches permitting theinterlocking of the bars with the webs of one set projecting beyond theflanges of the other set.

16. In a window assembly the combination of a frame bounding aventilating area and a movably mounted closure for the ventilating area,said closure having outwardly projecting flanges disposed in a planesubstantially parallel to the glazing of the closure, each of saidflanges having aligned spaced holes therein, a resilient weatherstripping member mounted intermediate the flanges and portions of theframe to seal the ventilating area when the closure is in closedposition, said resilient member having a plurality of alignedprojections provided with enlarged heads, said projections extendingthrough said apertures to hold the resilient member in position, andmeans for limiting the compression of said resilient weather strippingmember.

17. In a window assembly a frame bounding a ventilating area, said frameincluding a sill portion and inwardly projecting flanges along the sideand top portions thereof, a movably mounted closure hingedly attached tothe sill for closing the ventilating area, said closure including aplurality of aligned holes in each of the sides thereof and along thetop portion, a resilient weather stripping member disposed intermediatethe side portion and the top portion of the closure adapted to abut theinwardly projecting flanges of the frame to seal the ventilating areawhen the closure is in closed position, said resilient member includinga plurality of elongated members projecting through said alignedopenings and having enlarged heads adapted to hold the resilient memberin position, and means for limiting the compression of said resilientweather stripping member.

, 18. In a glazed window assembly a set of T- shaped muntin bars havingthe webs thereof projecting outwardly from the flanges, a second set oftransversely disposed T-shaped muntin bars having the webs thereof.projecting inwardly from the flanges, the first set of muntin barsintersecting the second set of muntin bars so as to divide the windowinto a plurality of spaces some of which are glazed leaving a group ofspaces vacant for ventilation, a movably mounted closure for the vacantspaces, and screens having frames supported by the muntin bars, saidframes being located on the outside of the flanges of the flrst set andon the inside of the flanges of the second set so as to prevent the freepassage of bodies through the vacant spaces.

19. In a glazed window assembly, a set of T- shaped muntin bars havingthe webs thereof projecting outwardly from the flanges, a second set oftransversely disposed T-shaped muntin bars having the webs thereofprojecting inwardly from the flanges, the first set of muntin barsintersecting the second set of muntin bars so as to divide the windowinto a plurality of spaces some of which are glazed leaving a group ofspaces vacant for ventilation, a movably mounted closure for the vacantspaces, said movably mounted closure having surfaces arranged incontacting relation with respect to the flanges of one set of bars, andadditional closures supported by the muntin bars, said additionalclosures being located on the outside of the flanges of one set of barsand onthe inside of the flanges of the other set of bars so as to closethe vacant spaces.

20. In a window of the character described, a series of duo-functionaltransversely disposed bars dividing the window into a multiple ofspaces, said bars functioning as detention bars and also as supports forthe window glass, some of the spaces being glazed, other left vacant toform a ventilating area, the bars bounding the ventilating areapresenting irregular contact surfaces, and an adjustable closure forsaid ventilating area, said closure having contacting surfaces adaptedfor engagement with the irregular contactsurfaces of the muntin barsbounding the ventilating area.

21. A detention window including transversely disposed muntin barsdividing the window into a plurality of spaces some of which are glazedleaving a group of spaces vacant as a ventilating area, thecontinuations of the bars extending across the ventilating areafunctioning as detention bars, the muntin bars of opposite sides of theventilating area differing in contour from the muntin bars extendingacross the ends of the ventilating area, and an adjustable closure forthe ventilating area, said closure being adapted to contact the muntinbars extending along the sides and adapted to contact the difle'rentlycontoured muntin bars extending across the ends of the ventilating area.

22. In window assembly of the character described having a ventilatingarea bounded by a frame which presents like surfaces on opposite sidesof the ventilating area, the portions of the frame extending across theends of the ventilating area being differently contoured from thoseextending along the sides thereof, and a pair of closure units for theventilating area, one of said closure units being adapted to be seatedbetween the frame members bounding the sides of the ventilating area,the second closure unit being movably mounted and provided withcontacting surfaces adapted to engage the frame extending along thesides of the ventilating area and also adapted to engage the differentlycontoured frame portions extending across the ends of the ventilatingarea.

WIILIAM D. BAYLEY.

